1. Field of the Invention
The present invention relates to plates adapted for reinforcing standard wooden door frames used in private homes- For steel doors with inner wooden body, the present invention relates also to reinforcing plates to be located in the vicinity of the bolt of the lock. The combination of the reinforced door frames and doors renders theft by breaking in through the door almost impossible.
2. Description of the Prior Art
The door frames are generally manufactured with soft wood, from coniferous trees such as the western cedar or the pine, the latter breed being the most popular. These frames are advantageous in that they are economical, easy to shape, and do not necessitate specialized tools and labor for their installation. However, they are disadvantageously sensitive to wear resulting from friction; they are flexible under torsion when forces are applied thereon in the horizontal direction of their fiber components and in the medium term they can split along their length. This is the result of the natural drying of the fibers which tend to separate; this last phenomena can, for instance, be observed on beams or planks made of oven-dried pine. These door frames are particularly vulnerable to break-ins during thefts since, as mentioned hereinabove, they are flexible at their center, that is the wood piece that constitutes them has an optimal force if it is pushed from the front or from behind, but has limited force if subjected to a swiping lateral thrust. This is due to the nature of the wood, that is to the orientation of the wood grain. Thus, to overcome this deficiency, we must look to reinforce the wood. This can be done by adding on the surface of the wood or by introducing in the wood rigid plates which will assist the wood in its work without hampering or altering the intrinsic qualities thereof. Moreover, the plates add to the door frame the necessary resistance to torsion when a lever is used to force the door and this at a relatively low cost with respect to the efficiency which is obtained.
For residential steel doors, it is necessary to reinforce the door, because the handle, the latch and the bolt are weakly connected by a casing made of a thin and non-structural metal, say of a soft wood frame. The prior art reveals amongst others two Patents having similarities with respect to the reinforcement systems that I have conceived. U.S. Pat. No. 1,010,365 discloses a S-shaped plate acting as a closing latch and mounted on the surface of the door as a movable S-shaped part. The use thereof was different and in relation with the type of closure used at that time. These S-shaped parts were mounted on the surface of the door, whereas in my system the S-shaped plate is hidden in the door frame and is fixed thereto, and the dead bolt is received in my S-shaped plate which is located on the inside of the door frame thereby constituting a whole or unit which is a lot more resistant.
As for U.S. Pat. No. 5,031,946, there is disclosed therein a reinforcing plate for a door which includes protruding rods and which is in fact a L-shaped reinforcing system having a double latch with one side of the "L" being mounted at the surface of the door without an adhesive contact with this surface, while its other side has adherence rods fixed internally in the door. This system does not take into consideration the handle and it can only be used on one side of the door, meaning that it can reinforce the door on only one of its sides. Finally, it is not much protected against torsion and thus it is subject to be dislodged by jamming.